#define ll long long
#pragma warning(disable : 4996)
#include <iostream>
#include<string>
#include <cctype>
#include <algorithm>
#include <cstring>
#include <cmath>
#include<cstdio>
using namespace std;
struct zuobiao
{
	int x;
	int y;
}z[1000001];
int p[1005][1005],n,m,ans;
int xj[] = { 0,0,1,-1 };
int yj[] = { 1,-1,0,0 };
bool v[1005][1005];
bool bfs(int s)
{
	int l = 0, r = 1;
	z[1].x = 1; z[1].y = 1;
	memset(v, 0, sizeof(v));
	while(l<r)	
	{
		++l;
		v[z[l].x][z[l].y] = 1;//这里已经标过了
		for (int i = 0; i <= 3; ++i)
		{
			int xx = z[l].x + xj[i];
			int yy = z[l].y + yj[i];
			
			if (xx<1 || yy<1 || xx>n || yy>m)
				continue;
			if (p[xx][yy] <= s && v[xx][yy] != 1)
			{
				z[++r].x = xx; z[r].y = yy;
				v[xx][yy] = 1;//为何删掉这句就不对了
			}
			if (xx == n)return 1;
		}
		
	}
	return 0;
}
int main()
{
	
	cin >> n >> m;
	int max = 0;
	for(int i=1;i<=n;++i)
		for (int j = 1; j <= m; ++j)
		{
			cin >> p[i][j];
			if (p[i][j] > max)
				max = p[i][j];
		}
	int zb=0, yb=max;
	while (zb <= yb)
	{
		int mid = (zb + yb) / 2;

		if (bfs(mid))
		{
			yb=mid-1;
			ans = mid;
		}
		else zb=mid+1;
	}
	cout << ans;
	return 0;
}